Forensic tests -which could take two weeks to complete - will now be carried out, but it is understood investigators are satisfied they originate from the R116 tragedy on March 14.

The entire Rescue 116 crew were killed in March after their helicopter clipped Blackrock Island off the coast of Mayo killing all four Capt Dara Fitzpatrick, Capt Mark Duffy and winch men Paul Ormsby and Ciaran Smith.